The superfamily of chemokine, which has chemotactic effects, belongs to cytokine. It plays an important role in immune defense, immunoregulation, inflammation, the proliferation and differentiation of stem-cells. At present, chemokine has been one of the hot points all over the world. The present inventors, by using suppression subtractive hybridization (SSH) technique, identified and cloned CKLF1 gene, a novel human cytokine with chemotactic effects, from a cDNA library derived from U937 cell line stimulated by phytohemagglutinin (PHA). The open reading frame of CKLF1 cDNA encodes a protein of 99 amino acid sequences. Its GeneBank access number is AF096895. It displayed chemotactic activities in a wide spectrum both in vitro and in vivo. Especially one in vivo study showed that the intramuscular injection of CKLF1 plasmid DNA into BALB/c mice caused inflammation in the lung, which mimicked the phenomena observed in chronic persistent asthma, an allergic lung inflammation. CKLF1 has been described in Chinese patent No. 99107284.7 and corresponding PCT Application No. PCT/CH00/00026 (International Publication number of WO 00/69910). Based on CKLF1, the present inventors obtained new polypeptides of the present invention.